package collection;

import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;

public class ListDemo1 {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();
        list.add("one");
        list.add("two");
        list.add("three");
        list.add("four");
        list.add("five");
        System.out.println("list:"+list);

        String e = list.get(3);//获取下标为3位置的元素
        System.out.println(e);
        for (int i=0;i<list.size();i++){
            System.out.println(list.get(i));
        }
        System.out.println("-------------------");

        list.set(2,"six");//将下表为2位置的元素替换为six
//        String a = list.set(2,"six");
//        System.out.println(a);
        System.out.println(list);

        String str = "老师你好";
        byte[] utf = str.getBytes(StandardCharsets.UTF_8);
        System.out.println("字符串长度为:"+utf.length);

    }
}
